//http://www.adequatelygood.com/JavaScript-Module-Pattern-In-Depth.html
define([], function() {
    // Forces the JavaScript engine into strict mode: http://tinyurl.com/2dondlh
    //http://stackoverflow.com/questions/246801/how-can-you-encode-to-base64-using-javascript
    "use strict";

    return {
        _keyStr: "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=",
        _utf8_encode: function (string) {

            var utftext = "", c, n;

            string = string.replace(/\r\n/g,"\n");

            for (n = 0; n < string.length; n++) {

                c = string.charCodeAt(n);

                if (c < 128) {

                    utftext += String.fromCharCode(c);

                } else if((c > 127) && (c < 2048)) {

                    utftext += String.fromCharCode((c >> 6) | 192);
                    utftext += String.fromCharCode((c & 63) | 128);

                } else {

                    utftext += String.fromCharCode((c >> 12) | 224);
                    utftext += String.fromCharCode(((c >> 6) & 63) | 128);
                    utftext += String.fromCharCode((c & 63) | 128);

                }

            }

            return utftext;
        },
        _utf8_decode: function (utftext) {
            var string = "", i = 0, c = 0, c1 = 0, c2 = 0;

            while ( i < utftext.length ) {

                c = utftext.charCodeAt(i);

                if (c < 128) {

                    string += String.fromCharCode(c);
                    i++;

                } else if((c > 191) && (c < 224)) {

                    c1 = utftext.charCodeAt(i+1);
                    string += String.fromCharCode(((c & 31) << 6) | (c1 & 63));
                    i += 2;

                } else {

                    c1 = utftext.charCodeAt(i+1);
                    c2 = utftext.charCodeAt(i+2);
                    string += String.fromCharCode(((c & 15) << 12) | ((c1 & 63) << 6) | (c2 & 63));
                    i += 3;

                }

            }

            return string;
        },
        _hexEncode: function(input) {
            var output = '', i;

            for(i = 0; i < input.length; i++) {
                output += input.charCodeAt(i).toString(16);
            }

            return output;
        },
        _hexDecode: function(input) {
            var output = '', i;

            if(input.length % 2 > 0) {
                input = '0' + input;
            }

            for(i = 0; i < input.length; i = i + 2) {
                output += String.fromCharCode(parseInt(input.charAt(i) + input.charAt(i + 1), 16));
            }

            return output;
        },
        encode: function (input) {
            var output = "", chr1, chr2, chr3, enc1, enc2, enc3, enc4, i = 0;

            input = this._utf8_encode(input);

            while (i < input.length) {

                chr1 = input.charCodeAt(i++);
                chr2 = input.charCodeAt(i++);
                chr3 = input.charCodeAt(i++);

                enc1 = chr1 >> 2;
                enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
                enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
                enc4 = chr3 & 63;

                if (isNaN(chr2)) {
                    enc3 = enc4 = 64;
                } else if (isNaN(chr3)) {
                    enc4 = 64;
                }

                output += this._keyStr.charAt(enc1);
                output += this._keyStr.charAt(enc2);
                output += this._keyStr.charAt(enc3);
                output += this._keyStr.charAt(enc4);

            }

            return output;
        },
        decode: function (input) {
            var output = "", chr1, chr2, chr3, enc1, enc2, enc3, enc4, i = 0;

            if(input != undefined) {
                input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");

                while (i < input.length) {

                    enc1 = this._keyStr.indexOf(input.charAt(i++));
                    enc2 = this._keyStr.indexOf(input.charAt(i++));
                    enc3 = this._keyStr.indexOf(input.charAt(i++));
                    enc4 = this._keyStr.indexOf(input.charAt(i++));

                    chr1 = (enc1 << 2) | (enc2 >> 4);
                    chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
                    chr3 = ((enc3 & 3) << 6) | enc4;

                    output += String.fromCharCode(chr1);

                    if (enc3 !== 64) {
                        output += String.fromCharCode(chr2);
                    }
                    if (enc4 !== 64) {
                        output += String.fromCharCode(chr3);
                    }

                }
            }
            return this._utf8_decode(output);
        },
        decodeToHex: function(input) {
            return this._hexEncode(this.decode(input));
        },
        encodeFromHex: function(input) {
            return this.encode(this._hexDecode(input));
        }
        // TODO finish adding this. to the above and retest
    };
});

